Background: Estimation of post-mortem intervals (PMI) is a critical step in most un-witnessed death investigations. After death, bodies begin to decompose in regular patterns which are used to estimate physiological time of death. These changes occur in widely variable ways and no single factor accurately indicates PMI. Objectives: This work aimed to compare between two different methods in estimation postmortem interval which are histopathological changes in suprarenal gland and vitreous humor potassium level. Materials and methods: The study was conducted on 50 Newzeland male rabbits, at the beginning of the study the rabbits were sacrificed by cervical dislocation then they were classified into 5 groups (I, II, III, IV, V) according to the PMI (0, 6., 12., 18 and 24 hours ) respectively. Histopathological and histometric examination [chromaffin cell count (cell /100 μm2), medullary surface area (μm2) and total chromaffin cell count] for left suprarenal were done. Spectroscopic determination of vitreous humor potassium was done. Results: There was significant statistical increase in the mean value of chromaffin cell count (cell/um2) and the vitreous humor potassium level (mEq/L) with increased PMI (P-value was 0.001). On contrast, there was significant statistical decrease in the mean value of the suprarenal medullary area (μm2) and total chromaffin cell count with increased PMI (P-value was 0.001). The results showed significant positive correlation between the vitreous humor potassium level (mEq/L) and chromaffin cell count (cell/100μm2). On the other hand the findings showed significant negative correlation between the vitreous humor potassium level
(mEq/L) and the suprarenal medullary area (μm2) and total chromaffin cell (P value was 0.001). Conclusion: The vitreous humor potassium level in combination with the chromaffin cell count (cell/100μm2), suprarenal medullary area and total chromaffin cell count can give more accurate estimation of the postmortem intervals.
Keywords: postmortem interval, suprarenal gland, vitreous humor potassium.